Process for making low fat bacon

ABSTRACT

Bacon products having very low fat contents are provided from high fat sources which can include pork trimmings. The bacon products are made from a composite of two low-fat meat components. One of the low-fat meat components is processed from high-fat content meat trimmings which are comminuted, heated and centrifuged, preferably in conjunction with being phosphated, under specific processing conditions. The second low-fat component is desinewed to remove substantial amounts of fat associated with the sinew that is mechanically removed from whole muscle tissue. The bacon product has a total fat content of not greater than about 5 percent by weight.

BACKGROUND OF THE INVENTION

The present invention generally relates to processing of raw meat into avery low-fat meat having excellent functionality, as well as to meatproducts of the so-called fat-free variety. More particularly, thepresent invention relates to bacon products which have a very low fatcontent, which meat products originate from meat raw materials havingtypical fat percentage values for natural or conventional sources ofmeat protein. These sources are processed into bacon products which canbe made from pork or any other meat so as to provide a bacon product ofextremely low fat content, including a product falling within thefat-free category. As employed herein, the term "meat" refers to beef,pork or ham, turkey, chicken or other fowl, or any other edible fleshproducts suitable for use as food.

The level of fat included in diets is of concern in many channels,particularly with respect to meat products or foods which containanimal-originating meat components. Meat food products are availablewhich fall into the generally low-fat category. For example, importantprogress has been made in providing uncooked raw meat supplies whichhave what might be considered to a low-fat content, on the order ofabout 10 weight percent or even 5 weight percent, based upon the totalweight of the raw meat supply. Traditionally, many meat products havebeen perceived by certain groups as being products that are relativelyhigh in fat content. Some of these are bacon type products.

Various bacon, bacon-like or bacon-appearing products have beendeveloped over the years. For example, it is generally known to combinesources of meat and/or vegetable and to form same into a shape of afinished product or of an intermediate product. It is also heretoforeknown that two or more different meat and/or vegetable compositions canbe coextruded into a simulated meat block or product. In one such anapproach, layers of differently appearing turkey batters are coextrudedin an alternating manner in order to form a simulated bacon slab whichhas a fat level lower than traditional pork belly bacon but notnecessarily very low fat or fat-free. Such a slab is then suitable forslicing in a generally conventional manner. Often, these slices areshingled and packaged for consumer distribution during normal tradechannels for bacon products. While these types of products fill animportant commercial need, other needs are not met.

It would desirable to have a bacon type of product which can be of thelow-fat variety but which need not be composed of turkey. It would beparticularly important from a taste and texture point of view if such asimulated bacon product could be a pork product when such is desired,but a pork product that still falls within the low-fat category. Evenmore desirable would be such a product which is very low in fat,preferably one which can be designated as fat-free.

More particularly, consumer perception has developed to the extent thatthere is a desire to have bacon-like products which are even lower infat content than a typical low-fat level of 5% or less. Ideally, havingsuch a product fall within the fat-free category is especiallydesirable. The term "fat-free" is meant to correspond to currentguidelines which are followed by the USDA permit many packaged meatproducts to be labelled as "fat-free" provided the amount of fat in thepackaged, meat product is less than 0.5 gram of fat per the nutritional"reference amount" of grams per serving of the meat product. Thistranslates to a weight percent which can vary depending upon particularmeat products. Such a product can thus be properly designated as "free"of fat, and nutritional labeling properly specifies a zero ("0") as thereported fat content.

Certain fat-free meat products which meet governmental guidelines suchas discussed above have been commercialized on a production-scale basis.Typically, these are fat-free turkey and chicken whole muscle (oftenbreast) products. Other fat-free products have been formulated fromtraditionally higher fat content sources. Such products can includereformulation in order to reduce fat levels by the inclusion of non-meatcomponents to generally dilute the fat present in the meat which isincluded within the batter, grind or emulsion from which such a productis formed. It is often the case that these types of fat-free products,when subjected to taste tests, score significantly lower thancorresponding products which are not of the fat-free variety.

Proposed approaches in the past have included processing a relativelyhigh-fat meat supply into one that is of reduced fat content. Often,these types of procedures include cooking, grinding and/or centrifugingas a basic approach for separating a fat-rich phase from another phasehaving a lower fat content. The phase having a lower fat contenttypically contains lean fractions which unfortunately had becomedenatured during processing, and the functionality of this phase oftenis reduced substantially, rendering it unsuitable and/or undesirable foruse in many applications. Also, approaches such as these often do notprovide a functional, reduced fat meat having a fat percentage on theorder of the low-fat or no-fat products which are the subject of thepresent invention.

The present invention addresses the need for reduced fat meat which hasan exceptionally low-fat content so as to qualify as having a zeroreported fat content, even including pork, while at the same time notbeing denatured to any significant extent in order to thereby provide ahighly functional meat product which is exceptionally low in fatcontent. It is especially desirable that a fat-reduced raw meat materialbe provided which makes possible the preparation of bacon types ofproducts. Substantial progress along these lines has been made byapproaches such as that of U.S. Pat. No. 5,382,444, incorporatedhereinto by reference. By following approaches such as this one, it hasbeen possible to provide valuable undenatured and very low-fat meatproducts, but not necessarily fat-free products and/or low-fat productsof pork and other meats having relatively high natural fat contents.

Fat-reduction of the types generally mentioned hereinabove reduce themeat to small sized pieces. For example, various such procedures reducethe fat content of meats to levels lower than might otherwise be readilyachieved by manual or hand trimming. Typically, these include heating ofthe meat, grinding or comminuting of the meat to small particle sizes,centrifuging, treating with selected additives or diluents and/or addingnon-fat supplements to reduce the percentage of pre-existing fatrelative to the total mass without actually removing fat. Theseprocedures have been employed singly or in some varying degrees ofcombination. Each has its disadvantages. Heating frequently results insome measure of denaturization. Grinding or comminution provides aquality and appearance which can be unacceptable where whole muscletissue is expected or desired. Addition of diluents, additives orsupplements alters qualities to an undesirable extent. Moreover, each ofthese fat removal or dilution procedures fails to remove sinew from themeat and therefore fails to address disadvantages attendant to thepresence of sinew, including toughness, chewiness and/or the presence offat cells associated with or attached to sinew.

As used herein, the term sinew refers to gristle and other connectivetissues which are naturally incorporated with muscle tissue. This sinewis generally intimately interwoven with the muscle tissue. Fattydeposits are associated with and attached to the intimately interspersedsinew, which is typically not susceptible to removal by hand trimming,for example. The present invention recognizes that the removal of asignificant and substantial portion of sinew without grinding the meatis an important objective, coupled with the objective of using such meatin making bacon products according to the invention.

SUMMARY OF THE INVENTION

Assembled bacon product according to the present invention incorporatesdesinewed whole muscle meat which is shaped and formed into a meatproduct or meat block. Such can be characterized as bacon product of thepork belly variety, bacon product from pork loin raw materials,so-called Canadian bacon, or the like. The product may have a two-phaseappearance or give the appearance of a more homogeneous product. Whetherhomogeneous or multi-phased, the bacon product according to theinvention incorporates multiple meat components. One or both of the meatcomponents are prepared from meat supplies having a substantial fatcontent, typically in excess of 20 weight percent, based upon the totalweight of the meat supply which also includes protein and moisture. Thisraw meat material is processed so as to provide reduced fat meatcomponents which can meet the fat-free requirements for the particularproduct category. Such will have a fat content equal to or less thanabout 3.5% fat or 2% fat, typically less than about 1.5% fat, even forpork from which it is especially difficult to remove bound fat below the1.5 weight percent level. Furthermore, both meat components have thefunctionality of a raw material meat supply.

Typically, in preparing one of these meat components, comminuted rawmeat trimmings are heated to a temperature and under conditions at whichfat present in the raw trimmings will liquify and its viscosity will beminimized, but protein denaturation will be substantially completelyavoided. The heated comminute is passed through a suitable centrifuge,preferably in combination with a phosphate mixture, to separate most ofthe fat content of the meat trimmings from an enhanced fat-reduced rawmeat product having enhanced functionality.

The other meat component of the bacon product can be a desinewed wholemuscle meat. It is prepared by desinewing of meats by physically andmechanically removing the sinew from the meat and its muscle tissue.Removal of a significant and substantial portion of the sinew isachieved in order to substantially upgrade and improve the quality andvalue of the meat while removing a very large proportion of the fat whenthe sinew is removed. Accordingly, muscle tissue of even porcine origin,meats from which it is typically more difficult to remove or reduce thefat content, may be substantially reduced in fat to highly desirable fatlevels of less than about 3 weight percent, most often less than about 2weight percent, and in many instances to less than about 1 to 11/2weight percent fat, based upon the weight of the meat component.Generally speaking, the separating of muscle tissue from sinew includesrestraining the sinew against movement relative to a surface andimparting a compressive force to the muscle tissue in a direction towardthe surface while restraining the sinew. The force is sufficient toseparate the muscle tissue from the sinew and cause the muscle tissue tomove away from the restrained sinew in a direction at a substantialangle to the direction in which the compressive force is imparted to themuscle tissue.

It is accordingly a general object of the present invention to providean especially reduced fat meat from meat trimmings having a much higherfat content and which are processed separately, at least one of whichbeing meat muscle tissue from which sinew has been removed.

Another object of the present invention is to provide a very low fatextruded bacon product with a homogeneous appearance.

Another object of this invention is to provide a very low fat extrudedbacon product having an appearance of light and dark streaks byco-extruding different lean materials.

Another object of the present invention is to provide a restructuredbacon product which is extremely low in fat but yet is made from porksources or other traditionally high fat sources.

Another object of the present invention is to provide a bacon productand process which provides a fat-free or "no-fat" bacon.

Another object of this invention is to provide a multi-phase baconproduct having a light-colored phase from which heme pigments have beenextracted and/or a dark-colored phase to which heme pigments have beenadded.

Another object of this invention is to provide an improved fat-reducedbacon product having superior functionality which is substantially thesame as that of naturally-occurring bacon products.

Another object of the present invention is to provide fat-reduced meatproducts such as fat-reduced pork, beef, turkey, chicken and mutton byprocessing such trimmings according to procedures by which virtually allof the fat is removed from the supply of meat trimmings while avoidingany substantial detrimental effect on the functionality of the meattrimmings.

Another object of this invention is to provide reduced fat meat baconproducts having a ratio of water-holding capacity to protein percentage,designated as functionality, which is equal to or greater than 3 andpreferably equal to or greater than 4.

Another object of the present invention is to provide low-fat orfat-free bacon products incorporating a phase of fat-reduced meat whichhad been conditioned with phosphates for effecting removal of fat thatwould otherwise remain bound within the meat except for the inclusion ofthe phosphate source.

Another object of the present invention is to provide finished porkbacon products which can have taste and texture attributes closer tothose of finished products prepared from traditional bacon sources suchas loins and/or bellies, especially when compared with bacon-typeproducts which do not originate from pork sources.

Another object of the present invention is to provide an improved baconproduct that has a fat content which is at or below respectiveregulatory definitions of fat-free meat products, including those underthe regulatory categories of bacon, red meat breakfast strips andpoultry breakfast strips, whether ready-to-serve or ready-to-cook.

Another object of this invention is to provide an improved fat-freebacon product, including such products originating from pork cuts, whichhas a nominal fat content of zero.

These and other objects, features and advantages of the presentinvention will be clearly understood through a consideration of thefollowing detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

In the course of this description, reference will be made to theattached drawings, wherein:

FIG. 1 is a flow chart illustrating a preferred overall procedure formaking a two-phase bacon product in accordance with the presentinvention;

FIG. 2 is a generally schematic view of an early portion of a preferredprocedure for providing one phase, which can be a light-colored phase,wherein meat trimmings which are not in a comminuted state are reducedin particle size;

FIG. 3 is a generally schematic view of a portion of the illustratedprocedure and which is subsequent to FIG. 2, wherein the temperature ofthe comminuted meat is continuously, rapidly and evenly modified;

FIG. 4 is a generally schematic view illustrating passage of the warm,comminuted meat supply from FIG. 3 through a continuous decantercentrifuge in order to form this phase;

FIG. 5 is an illustration of a preferred apparatus and procedure forproviding the other phase, such as a dark-colored phase, used in makingthe bacon product according to the invention, such being a plan view ofan assembly for desinewing and for practicing the method of separationof sinew from muscle tissue;

FIG. 6 is a partially broken away, cross-sectional side elevational viewof the assembly substantially as shown in FIG. 5 and viewedsubstantially along the line 6--6 of FIG. 5;

FIG. 6A is a schematic plan view of the pin plate of the assembly shownin FIGS. 5 and 6 and showing a preferred embodiment of pin arrangementand flow direction of desinewed muscle tissue which has been separatedfrom sinew;

FIGS. 7, 8, 9, 10 and 11 are partially broken away, cross-sectional sideelevational views of the desinewing portion of the assembly,substantially as shown in FIGS. 5 and 6, and showing the positioning andoperation of several component parts of the desinewing unit duringvarious chronological incremental steps in the illustrated desinewingmethod; and

FIG. 12 is a plan view sketch of a typical web of sinew followingseparation and removal from the muscle tissue of the meat making up thephase prepared according to FIG. 5 through FIG. 11.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Certain specific information specified herein is directed to embodimentswherein the low-fat, no-fat or fat-free bacon product originates fromporcine meat cuts. It will be understood and appreciated that theprinciples of the invention can be applied in a similar fashion to othermeats and meat-like sources. The fat-containing raw materials which aretransformed into the bacon products in accordance with the presentinvention typically are trimmings from meat processing operations. Thesetrimmings, typically collected by cutting away visible fat from themuscle, are high in fat content. Generally speaking, these raw materialmeat sources or trimmings have a fat percentage on the order of about 20to about 60 weight percent. Raw materials of this type are usually at atemperature on the order of about 40° F.

Examples of these raw material meat trimmings, which are generallyavailable in high volumes and at relatively low costs, include 72 pork(containing roughly 28% fat and 72% "lean", which is the portion of the72 pork is which is not fat, typically lean muscle which includesmoisture). Other trimmings in this regard are 42 pork (approximately 58%and 42% lean), 50 beef (approximately 50% fat and 50% lean),mechanically deboned turkey (often between about 20% and 30% fat), andother sources of red meat, white meat, fowl or other protein sources.

Food products are entitled to be labeled as fat-free or no-fat when theymeet specific criteria. Generally, a meat product is to have less than0.5 gram of fat per reference amount and serving size. Governmentalregulations set the reference amount values, which can be different fromproduct to product. For example, current U.S. regulations are asfollows. The reference amount for red meat bacon, on a cooked basis, isper 15 grams, meaning that such a fat-free product can have up to 3.33weight percent fat. On a raw basis, the reference amount for this samecategory is 54 grams, allowing up to 0.94 weight percent fat. For thered meat breakfast strip category, the ready-to-cook reference amount is30 grams, allowing up to 1.67 weight percent fat. When in a ready-to-eatform, this same category has a reference amount of 15 grams, allowing upto 3.33 weight percent fat. For poultry products, the reference amountfor ready-to-cook is 26 grams, allowing for up to 1.92 weight percentfat. In the ready-to-eat version, the reference amount is 15 grams. Thesame is the case for ready-to-eat poultry breakfast strips, allowing upto 3.33 weight percent fat. A ready-to-cook poultry breakfast strip hasa reference amount of 18 grams, allowing up to 2.78 weight percent fat.Accordingly, fat-free bacon types of products can have total maximum fatcontents ranging between 0.93 weight percent and 3.33 weight percent,depending upon the particular product category within which the productis classified.

FIG. 1 illustrates a preferred procedure for forming a multi-phasedbacon product according to the invention. Further details in connectionwith preparing one phase, typically the light-colored phase, areillustrated in FIGS. 2, 3 and 4, while further details in connectionwith preparing another phase, typically the dark-colored phase, areillustrated in FIGS. 5, 6, 6A, 7, 8, 9, 10, 11 and 12. The respectivephases can be varied as desired from that shown in these specificillustrations. Generally speaking, the first or light-colored phase ofthe illustrated embodiment is prepared from fatty pork loin trimmingswhich are subjected to particle and temperature modification, followingby centrifuging into fat and lean components. This procedure isgenerally in accordance with U.S. Pat. No. 5,382,444, U.S. Pat. No.5,688,549 and U.S. Pat. No. 5,762,993, the subject matter of these beingincorporated by reference hereinto. Thereafter, the highly functionallean component is combined with a second or dark-colored phase asgenerally discussed herein.

In the embodiment illustrated in FIG. 1, this highly functional leanground meat material can be made to have a somewhat lighter color thanthe color of the meat coming off the centrifuge. When a lighter coloredphase is required, the lean centrifuged product is mixed with water toextract heme pigments. More particularly, about 15 to 30 weight percentwater is added to, mixed with and drained from the lean centrifugedproduct. This extracts water-soluble heme pigments. This pigmentedextract can be combined with the second or dark-colored phase in orderto further darken same and avoid the loss of useful nutrients in thefinal bacon product.

Whether or not the heme pigment extraction takes place, it is usuallydesirable to emulsify the centrifuged lean material with brinecomponents. The emulsified lean and brine material can then beco-extruded with the dark-color phased as described herein. Atraditional brine or brine-like aqueous composition is typicallyprimarily water and includes at least about 0.5 weight percent salt.Brine compositions can contain as high as about 5%, or even 8% salt,depending upon the desired final product. Flavoring and othercomponents, such as preservatives and components useful for improvingthe firmness of the completed light-colored phase of the bacon productcan be included in the water composition. Exemplary components in thisregard include salt, sodium nitrite, sodium ascorbate or the like, sugarand other ingredients. In an illustrated approach, the aqueous brinecomposition can be added to the centrifuged lean meat at a ratio ofabout 60 to 70 pounds of brine composition per 100 pounds of lean meatcomponent.

The apparatus illustrated in FIGS. 2, 3 and 4 includes a particle sizereduction station, generally designated as 11 in FIG. 2, a temperatureadjustment station, generally designated as 12 in FIG. 3, and acentrifugation station, generally designated as 13 in FIG. 4. Althoughnot shown in the drawings, it will be appreciated that these variousstations are in communication with each other whereby meat materialprocessed at an upstream station is passed to a receiving area of thenext downstream station, as will be discussed in greater detailhereinafter.

Particle size reduction station 11 reduces the grind size of thefat-containing raw meat material to comminuted particle sizes.Generally, coarsely ground raw meat is supplied into a dumper 15 forpassage into a transporting mechanism such as a pump feeder 16 ofgenerally known construction including members such as a positivedisplacement pump 17 and a flow meter 18. Meat is thereby fed into acomminution unit 19 in order to reduce the particle size of the groundmeat to form a flow of comminuted meat. It will be appreciated that somefat-containing raw materials such as mechanically deboned turkey areprovided in a generally comminuted state, and the particle sizereduction station 11 could be omitted in this instance.

A preferred comminution unit 19 is a Cozzini grinding device or emulsionmill wherein a plate having three protruding knives spins tightlyagainst a plate having 4.5 mm holes therewithin. A rotating vane memberpumps the comminuted meat through and out of the comminution unit andinto a transfer conduit 21. These types of devices are high-speedgrinders, and the bladed plate is pressure fit against a foraminousplate. The meat raw material is fed through a pipe into the emulsionmill housing and engages the rotating blades to be severed to a sizewhich passes through the holes in the plate. Conduits in addition totransfer conduits 21 such as the two which are partially shown in FIG. 2can also be provided whereby a single particle reduction station 11 cansupply a flow of comminuted meat to more than one temperature adjustmentstation 12.

In one embodiment which includes the addition of phosphate into thesystem, an upstream injector 20 can be provided as shown in FIG. 2. Thisupstream injector deposits a phosphate source into the raw trimmings. Asan example, this upstream injector 20 can open into the dumper 15 orinto any other suitable container at or upstream of the pump feeder 16.Generally, this upstream location is preferred when the phosphate sourceis a complex one which might require some time in order to break downinto a mono-type of phosphate. When the powdered buffering salt orphosphate is added in a so-called polymeric state, for example as sodiumtripolyphosphate, adequate time must be available in order to releasediphosphate forms for achieving the result in accordance with theinvention by the time that the flow of meat enters the downstreamcentrifuge, as discussed in more detail hereinafter.

Another embodiment concerning the phosphate addition incorporates a drysolids injector 40 positioned upstream of the temperature adjustmentstation 12 and of the centrifuge assembly. Injector 40 forces theparticulate or powdered buffering salt or phosphate into the meat flow.The injection is such that the phosphate enters into the continuouslyflowing meat stream in a manner that fosters blending into and with themeat flow. With this embodiment, it is preferred that the phosphategroups not be tied up in chemical complexes when this embodiment ispracticed. In this regard, a diphosphate or the like is typicallypreferred when the fat removal enhancing phosphate is inserted by meansof the downstream dry solids injector 40.

With more particular reference to the comminution which is typicallycarried out at the particle size reduction station 11, the objective isto provide a very finely ground raw meat, although the grind is not tobe excessively fine. Often, one can detect meat fibers in the comminutedmaterial. Near emulsion grinds are accomplished. The grind is to be fineenough so that many cells of fat are broken, while avoiding the breakageof so many fat cells that a true emulsion is formed at this stage andthe protein material again wraps around fat particles so as to interferewith separation of protein from fat. Typically, the particle size willbe less than about 2 mm, preferably less than or equal to about 1 mm. Inan especially preferred situation, the meat particles or muscle fiberpieces are approximately 0.1 to 0.6 mm in length and approximately 0.06to 0.1 mm in diameter. Other sizes are feasible as well.

Excessive comminuting can be indicated by too great of a rise in thetemperature of the raw meat when it passes through the particlereduction station 11. For example, if the comminuting unit is operatingunder conditions such as a grinder speed which is too harsh for the flowrate through the comminuting unit, the particle size can be made toosmall and/or the temperature rise can be too great. It is believed thatthe detrimental result thereof is that the lean and fat begin toseparate too early in the process, thereby making more difficultseparation at subsequent stations. Also, excessive comminuting can beaccompanied by some evidence of denaturing of protein.

As stated, raw fat-containing material passing through the particle sizereduction station 11 will be raised in temperature as a result of thegrinding operation. Typically, the temperature rise will need to beadjusted at the temperature adjustment station 12. A feeder pumpapparatus 22 directs the supply of comminuted meat to a heat exchangerassembly 23.

Preferably, the heat exchanger assembly raises the temperature of theflow of comminuted meat so that the temperature of substantially theentire flow of meat therethrough is high enough to release the fat inaccordance with the approach discussed herein and is typically notgreater than about 115° F. (about 46° C.) or slightly thereabove. It isimportant that the temperature be closely controlled and that thistemperature be controlled for all of the meat passing through thetemperature adjustment station 12. Preferably, the temperatureadjustment station 12 should maintain the desired temperature to such anextent that it is possible to maintain a target temperature ±1.5° F.(about 1° C.) for virtually all of the comminuted meat flowing throughthe heat exchanger assembly 23. Generally, the processing residence timewithin heat exchanger assembly 23 will be for less than ten minutes,preferably less than five minutes. Inclusion of one or more swept orscraped surface heat exchangers or wiped-film heat exchangers arepreferred for achieving this objective.

Temperature adjustment station 12 preferably also includes a flow meter24 and a temperature sensor 25, as well as a recirculation conduit (notshown) and an outflow conduit 26. For example, in the event that thesensor determines the temperature of the meat exiting the heat exchangerassembly 23 is not within the designated tolerances, the meat flow willbe recirculated and passed again through the heat assembly 23. The heatexchanger assembly can include a water jacketing arrangement whichincludes a steam supply unit, generally designated as 27, a waterreservoir 28, centrifugal pumps 29, flow control valves 31 andrecirculation channels 32.

Heated comminuted meat flows out of an exit conduit 33 of thetemperature adjustment station. At this stage, the comminuted meattemperature of all of the meat flowing through the exit conduit 33 willbe lower than 120° F. (about 49° C.), preferably not greater than about115° F. (about 46° C.). It has been found that, with most comminutedmeat, if the temperature is raised to 120° F. (about 49° C.) for anysignificant length of time, a substantial quantity of the proteintherein becomes denatured and loses its natural raw functionality.Similarly, the denaturation process typically is initiated attemperatures equal to or greater than about 115° F. (about 46° C.) ifthe comminuted meat is subjected to temperature much above this rangefor a short a time period as 5 seconds. Temperatures as low as about 90°F. (about 32° C.) or below can be adequate for some meats when longertime periods are practiced. A preferred lower limit is about 90° F.(about 32° C.), a more preferred lower limit being about 100° F. (about37.8° C.). It will be appreciated that the exact temperature will varywith the meat source and also with the residence time. The temperaturemust be high enough for the particular meat source and under theparticular time and flow conditions, so that optimum separation can beachieved during the subsequent steps. By closely controlling the optimumtemperature for the particular meat and system, protein and fatoverheating is avoided while providing the needed feed temperature intothe centrifugation system 13.

Centrifugation system 13 (FIG. 4) receives the heated flow of comminutedmeat. Preferably, the exit conduit 33 joins with a receiver 34 having apositive displacement pump 35 and a flow meter 36 into a continuousdecanter centrifuge assembly 37. At this stage, the meat flow has anappearance of the cross-section 14, having lean components and fatcomponents (the lighter colored portions of cross-section 14).

Referring to the operation of the decanter centrifuge assembly, samedecants a fat portion 47 off of a protein or lean portion 30 by relativerotation so as to impart gravitational forces on the heated, comminuted(and preferably phosphated) meat to accomplish the enhanced decantingfunction. This meat flow enters tube 38 and is flung therefrom through aplurality of exit holes 39 and to an auger assembly 41. Revolutions perminute of the continuous decanter centrifuge 37 are measured by atachometer 42, and the G-force is calculated from the revolutions perminute readings. The fat component 47 has a liquid consistency, and itexits the continuous decanter centrifuge 37 through openings 43. Anangled dam 44 is provided at an opposite end of the centrifuge 37, andthe auger assembly 41 augers the generally solid meat or proteincomponent 30 toward and along the angled dam 44 and out of thecentrifuge 37. The substantially liquid fat component cannot be augeredup to the angled dam 44 and thus exits through the openings 43.Accordingly, the liquid fat component flows through outlet 45, while themeat or protein component flows through outlet 46. The material flowingthrough the outlet 45 is a fat by-product which may be further processedor discarded as desired. Flow through the outlet 46 provides the low-fator no-fat meat product, illustrated by the cross-section 30, prepared inaccordance with the invention.

Typically, the temperature of the low-fat or no-fat meat flowing fromthe outlet 46 will be lowered promptly for reasons well known in the artin order to avoid any risk of developing microbiologically undesirableconditions in the meat or of denaturing the meat protein. It isimportant to note that, with the present process and apparatus, thelow-fat or no-fat meat product is not frozen, thereby avoiding aprocedure which can damage meat fibers. Usually, the time during whichthe product is within any cooling assembly will be not greater thanabout 10 minutes.

In addition to being able to provide low-fat or no-fat meats havingexceptionally low fat contents, the present apparatus and processprovide same with a functionality that is virtually indistinguishablefrom that of unprocessed raw meat. The functionality is such that thereduced-fat meat is readily combined with other component(s) of thebacon product. Generally speaking, functionality is calculated bydividing the gross water holding capacity by the percentage of proteinin the reduced-fat meat. It is generally believed that the presentinvention enhances the gross water holding capacity when meat processedaccording to the invention is compared with meat processed in accordancewith other approaches, such as others also including meat comminution.This enhanced gross water holding capacity is believed to be animportant indicator of the excellent functionality of the low-fat orno-fat meat. The present invention allows reduction of the fatpercentage of high-fat trimmings, including pork, to at or below about1.5 weight percent while maintaining the following functionalityparameters: a protein level of greater than 20%, a functionality inexcess of 3, and a hydroxyproline value below about 11 mg/g, preferablyless than 6 mg/g.

With more particular reference to the water holding capacity, excess orgross water binding is a measure of the extra swelling capacity for meatprior to cooking and is thereby a measure of the quantity and/or qualityof functional protein. This gross water holding capacity is calculatedby a procedure whereby the percent cook-out is determined and is used asa measure of meat quality with respect to cooking when proteins aremaximally hydrated. Regarding the hydroxyproline analysis of meat, thisis an amino acid found in collagenous protein, but not in contractileprotein. Thus, by quantitatively determining the hydroxyproline levelsin meat products, the collagen content of the sample is measured.

With further reference to typical fat-containing starting materials, 42pork is known as regular pork trim, and it will include about 58% fat,about 8% protein and about 34% moisture. Pork of the 72 pork trimvariety typically includes about 28% fat, about 15% protein and about57% moisture. Preferably, the low-fat or no-fat first or light-coloredphase pork according to the present invention will have on the order ofabout 1% fat, about 23% protein and about 76% moisture. Typically, thefat percent will be not greater than 1.5% fat, preferably about 1 weightpercent or less of fat, the levels going to as low as about 0.3 weightpercent fat.

Addition of the phosphate salt prior to centrifugation substantiallyenhances the fat removal achieved during centrifugation. Generallyspeaking, this timely phosphate addition reduces the weight percent fatcontent by about 0.2 to about 0.3, at times as high as about 0.5, weightpercentage points of fat-reduced content. As an example, for a reducedfat pork which, without phosphate addition, would have a fat content ofabout 1.5 weight percent, the phosphate addition according to theinvention results in a fat content of about 1.2 weight percent or below.Thus, the fat content of the fat-reduced pork is reduced by from about10% to about 40% by the addition of the phosphate source. Without thisaspect of the invention, it is very difficult to maintain a fat level ofbelow 1.5%, when the starting material is 72 pork.

Without being bound by any theory of a functional mechanism regardingthis invention, it is believed that the phosphate addition as discussedherein reduces the viscosity of the meat, resulting in the enhancedseparation of the fat component from the lean component which isaccomplished when the thus-treated meat is subjected to centrifugation.

It is well known that, in the actomyosin of pork and the like, myosinand actin "slide" with respect to each other. Phosphate causesdissociation or loosening of this muscle structure so that actin proteinand myosin can loosen and move around more easily in order to "release"fat components which would otherwise remain trapped in the meatstructure during centrifugation carried out in the absence of this addedphosphate. The phosphate is believed to provide a "softer" muscle which,when centrifuged, will "flatten out" so that the fat can separate moreeasily when the centrifuge takes advantage of the density differencesbetween fat and lean.

By loosening the actin from the myosin, the fat-rich material "inside"of the muscle can be more easily removed. This loosening is facilitatedby the phosphate use as described herein. In contrast, adipose tissue(fat tissue) is more easily removed because it generally sits on the"outside" of muscle bundles or strands. Thus, with pork, adipose tissuefat removal leaves about 2% to 3% fat, and phosphate addition providesfor removal of further fat, such as that associated with the actomyosinstructure, thereby allowing the fat percentages of 1.5 weight percentand lower as discussed herein.

Phosphate sources suitable for use include a variety of phosphate saltsand polyphosphates. As discussed herein, a polyphosphate may requiretime to dissociate so as to free individual diphosphate moieties whichare found to achieve the beneficial effect in accordance with theinvention. Thus, as a general rule, the more complex the phosphatesource, the more likely same will have to be added at an upstreaminjection location, rather than at a more downstream injection locationinto the meat flow. Generally speaking, the phosphate source can beadded at between about 0.1 to about 0.5 weight percent phosphate, basedupon the meat being treated. A preferred range is between about 0.2% andabout 0.5% phosphate. Generally speaking, higher levels do not furtherenhance fat removal and typically will be avoided. There is no desire toattempt to reach the isoelectric point of the meat, which is generallydetrimental to functionality.

Examples of phosphate sources include sodium pyrophosphate (adiphosphate), potassium pyrophosphate, sodium tripolyphosphate andpotassium tripolyphosphate. Also available and useful are blends ofsodium or potassium acid pyrophosphate, tetrasodium pyrophosphate,tetrapotassium pyrophosphate, potassium hexametaphosphate, sodiumhexametaphosphate or other such polyphosphates. They can be inparticulate form, which is preferred, or in liquid form, such as whenthe phosphate is within an aqueous carrier.

One preferred embodiment for providing the second or dark-colored phaseaccording to the invention is shown in FIGS. 5 and 6. Details of theoperation of that preferred desinewing embodiment of the assembly andmethod of this aspect of the invention are shown sequentially in FIGS. 7through 11. This is generally in accordance with U.S. Pat. No. 5,746,649its subject matter being incorporated by reference hereinto.

Referring to FIGS. 5 and 6, the assembly includes a frame 10 supportedupon a plurality of legs 112. One or more of the legs 112 preferablyinclude leveling feet 114 at the bottom to permit leveling of theassembly and to make certain that the assembly is firmly andstationarily supported upon the floor or other surface upon which it isto operate. It will be appreciated that firm rigid support of theassembly is desirable upon considering the operation of the assembly andthe substantial forces and movements which occur in various of itscomponents during its operation.

A conveyor 116 is positioned at the top of the frame 10. The conveyor116 preferably comprises an endless conveyor belt 118, which ispreferably formed of a hard, flexible strong polymer which is foodcompatible and which is capable of withstanding the substantial forcesand wear to which it will be exposed. Such polymers may includepolyethylene and the like. The conveyor belt 118 is trained around oneor more idler rollers 120 and 122 as best seen in FIG. 6 and also arounda powered drive roller 124. The drive roller 124 may be driven by asuitable motor 126 via either a pulley and belt drive or chain andsprocket drive 128. It will be appreciated that the location of theidler roller 122 and drive roller 124 may be reversed from that shown inthe drawing without departing from the principles of the invention.

The principal feature of the illustrated desinewing assembly is thedesinewing unit 130 of the assembly. In general the desinewing unit 130comprises two movable, force imparting subassemblies, a lift assemblygenerally 132 and a head assembly generally 134.

The lift assembly 132 preferably comprises at least four spaced,vertical lift posts 136 which extend through, above and beneath theplane of the upper surface of the conveyor belt 118, as best seen inFIGS. 6-11, and which straddle the conveyor belt, as best seen in FIG.5. A strong, rigid frame 138 is fixed at its corners to the bottom ofeach of the lift posts 136. A suitable drive means, such as areciprocating hydraulic cylinder 140, is stationarily fixed at one endto the frame 10, and its piston rod 142 which extends from the other endof the cylinder 140 is coupled by a suitable coupling 144 to the frame138. Preferably this piston rod coupling 144 permits some degree ofpivotal or rotational motion to compensate for variations in alignmentbetween the piston rod 142, the frame 138 and the spaced posts 136during their movement and operation.

In the embodiment shown, the lift posts 136 are reciprocated up and downby the hydraulic cylinder 140 and frame 138. As the lift posts 136reciprocate through the plane of the upper flight of the conveyor belt118, they are preferably guided by journals 146 which are mounted to asubstantially flat, heavy gauge rigid base plate 48. The base plate 48is of heavy and substantial construction so that it is capable ofreadily withstanding the forces to be applied to it during thedesinewing operation, as will be later described. The base plate 48presents an upper surface 50 upon which the conveyor belt 118 slides andis supported during the desinewing operation. Also in the embodimentshown, the upper end of the hydraulic cylinder 140 is shown as mountedto the underside of the base plate 48.

The upper ends of the lift posts 136 are fixed at the corners of arelatively heavy gauge plate 52 upon which the head assembly 134 ismounted. The plate 52 may be further stiffened with elongate stiffeners53. It will be seen that the plate 52 together with the head assembly134 will move up and down by virtue of the operation of the liftassembly 132.

A plurality of spaced, vertical head posts 54 are stationarily mountedat their tops to plate 52. The head posts 54 extend vertically downwardfrom the plate 52 and their bottoms are fixed to a compression assembly,generally 56.

The compression assembly 56 comprises a pair of spaced plates, an upperspacing plate 58 and a lower compression plate 60. The spacing plate 58and compression plate 60 are spaced from each other by any suitablemeans, such as a wall 62 as shown in the drawings, and the spacing ofthe plates 58 and 60 relative to each other is preferably fixed andremains unchanged during operation. The bottom ends of the head posts 54are fixedly attached to spacing plate 58 so that the spacing plate andhence the compression assembly 56 will move up and down in conjunctionwith the vertical movement of the head posts 54, the plate 52, the liftposts 36 and the lift assembly 132 generally.

The head assembly 134 also includes a pin plate 64 above the compressionassembly 56. A plurality of elongate pins 66 are fixed at their tops tothe pin plate 64 and so as to extend vertically downwardly throughapertures 68 in the spacing plate 58, and also through apertures 70 inthe compression plate 60. The pins 66 are preferably arranged in columnsand/or rows and the pins 66 of each column and/or row are preferablystaggered from each other as shown in FIG. 6A to also form diagonal rowsas shown. This will be discussed in more detail below. Accordingly, thepins 66 will be spaced from each other in the directions a, b and c asgenerally shown in FIG. 6A. It will be seen from FIGS. 6-11, that thepins 66 also preferably have blunt ends and are slidably movable throughthe apertures 68 and 70 and through the plates 58 and 60 as the pinplate 64 and press assembly 56 are moved relative to each other. The pinplate 64 is mounted for operation by a suitable coupling 72, preferablycapable of at least some degree of pivotal motion, to the piston rod 74of a power cylinder 76. The power cylinder 76 is preferably a pneumaticcylinder to preclude the possibility of undesirable leakage of hydraulicfluid which might result in contamination of the food products beingprocessed. The air cylinder 76, in turn, is mounted on the plate 52 forup and down movement therewith by the lift assembly 132.

The assembly embodiment shown in FIGS. 5 and 6 also preferably includessome form of positioning and delivery equipment for delivering the meatM which is to be desinewed to the input end of the conveyor 116 and toposition it so that it is properly aligned with the desinewing unit 130.This may comprise for example a hopper 78, as shown in FIGS. 5 and 6,into which the meat M to be processed may be deposited so as to fallupon the conveyor 118 as shown in FIG. 6, in a proper position to bereceived by the desinewing unit 130 upon indexing of the conveyor belt118. When the meat M is processed according to the invention to separateits desirable muscle tissue MT from the sinew, the muscle tissue MTcontinues to be indexed along the assembly, also as shown by the hollowarrows in FIGS. 5 and 6, for discharge and further formulation into thefinal consumer product. Guidance of this muscle tissue MT may befacilitated by way of siderails 80. This muscle tissue MT is thepreferred second lean phase or dark-colored phase component of the baconproduct.

Prior to discussing any further details of any of the remainingcomponents of the desinewing assembly embodiment shown in FIGS. 5 and 6,a description of the operation of the assembly and method as shown inFIGS. 5-11 and as thus far described to separate the muscle tissue andsinew from the meat M will follow next to facilitate a clearerunderstanding of this aspect of the invention.

The meat from which the sinew and/or fat which is associated with andattached to the sinew is to be removed is first deboned and cut intomanageable sized pieces. These pieces are preferably further handtrimmed to remove any large visually distinct and accessible collectionsof fat, gristle and the like. These pieces are also preferably cleanedof any connective tissue membrane which might be present because themembrane, like the sinew, harbors generally undesirable fat cellsassociated with it. The connective tissue membrane may be removed usingconventional membrane skinning equipment, such as a Maja or Townsendmembrane skinner.

These boneless trimmed pieces or cuts of whole muscle meat M which arenow to be processed are introduced to the input end of the conveyor belt118 and properly positioned thereon by deposit through the hopper 78.The hopper 78 is preferably stationarily mounted relative to the inputend of the conveyor belt 118 so that the meat M which is to be processedis properly positioned relative to the desinewing unit 130 as each pieceis introduced to the assembly and method of the invention.

The conveyor belt 118 is then indexed by a suitable control (not shown)as well known to those skilled in the art to progressively move the meatM which has been deposited on the conveyor belt 118 and from which thesinew is to be removed in the direction of the hollow arrows shown inFIGS. 5, 6 and 6A and from beneath the hopper 78 in progressive indexedsteps until it is beneath the desinewing unit 130. The location and sizeof the hopper 78 are selected relative to the length of each indexingstep so that once the meat M from which the sinew is to be removedreaches the desinewing unit 130, it is properly positioned bothlongitudinally and transversely directly beneath the press assembly 56and pin plate 64 and its pins 66, as shown in FIG. 6.

At this time the cylinder 76 of the head assembly 134 is actuated sothat its piston rod 74 will extend and move the pin plate 64 from theposition shown in FIG. 6 to the position shown in FIG. 7. As shown inFIG. 7, the pin plate 64 will move downwardly along head posts 54 untilit rests upon the upper side of the spacing plate 58 of the compressionassembly 56. As the pin plate 64 moves downwardly, its pins 66 will movefrom their retracted position as viewed in FIG. 6 to the position, asviewed in FIG. 7, in which their bottom ends extend from the surface 61of the compression plate 60.

The force applied to the pin plate 64 by the air cylinder 76 should atleast be of sufficient magnitude to be adequate for the pins 66 tostationarily restrain the sinew during desinewing as will be describedbelow. By way of example it has been found that a force of about3000-4000 pounds is adequate for this purpose where the pin plate hasabout 650 pins 66 which are about 1/4 inch in diameter, i.e. about 32in² of pins. If the number of pins and/or diameter is reduced, the forcemay be reduced, and conversely, if the number of pins and/or theirdiameter is increased the force should be generally increased in orderto be of sufficient magnitude to insure that the sinew is stationarilyrestrained during the desinewing operation. The maximum amount of forceis not critical and can be of any magnitude so long as it is sufficientto restrain the sinew against movement relative to the top surface ofthe belt 118 which is supported on the surface 50 of the base plate 48and the compression surface 61 of the compression plate 60 as will bediscussed below. Excessive forces are not preferred, however, becausethey are wasteful of energy and require heavier duty parts withoutachieving any appreciable further desirable result.

After the pin plate 64 has moved downwardly into contact with the uppersurface of the spacing plate 58 as shown in FIG. 7, the air pressure iscontinued to be maintained in the cylinder 76 at least during the nexttwo subsequent steps.

With particular reference now to FIG. 8, the lift assembly 132 is nowactuated by supplying fluid pressure to the cylinder 140. This willcause the piston rod 142 of cylinder 140 to extend to move the frame 138downward. As the frame 138 moves downwardly, it will move the lift posts136 downwardly together with the plate 52 at the top of the lift posts.Movement of the plate 52 downwardly will also cause the head assembly134 to also move downwardly with the cylinder 76 which is mounted to theplate 52 and the head posts 54 which also are firmly mounted to theplate 52. As the head posts 54 move downwardly, the compression assembly56, the pin plate 64 which already rests on the compression assembly,and the pins 66 will also move downwardly until the blunt ends of thepins pierce or skewer the meat M and come to rest forcefully bearingagainst the top side of the conveyor belt 118 which in turn is supportedby the upper surface 50 of the base plate 48, all as shown in FIG. 8.

With particular reference now to FIG. 9, the lift assembly 132 willcontinue to move downwardly. However, at this point the pins 66 havecome to rest against the top surface of the conveyor belt 118 and,therefore, the pin plate 64 and the pins 66 will be restrained fromfurther downward movement and will stop. The compression assembly 56,however, will continue to move downwardly and away from the pin plate 64because the downward force exerted by the cylinder 140 is substantiallygreater than the force exerted by the cylinder 76 on the pin plate 64and pins 66 as previously discussed. By way of example, it has beenfound that a force of about 5000-10000 pounds where the compressionsurface 61 is about 10 by 15 inches, i.e. about 150 in², is adequate tocompress the muscle tissue sufficiently to remove it from and move itaway and at a sharp angle from the sinew S which is restrained againstmovement relative to the conveyor 118, the surface 50 of the base plate48 and the compression surface 61 as in the present invention. Againthis force may be reduced somewhat if the compression surface 61 isreduced in size, and increased if the surface 61 is increased in size.And again, the maximum force is not critical, except that excessiveforces which produce no additional benefit are not preferred as beingwasteful and necessitating excessively heavy duty parts.

The compression assembly 56 will continue to move downwardly until itassumes its most downward position shown in FIG. 9. In this position thecompression surface 61 of the compression plate 60 will exert asubstantial compression force upon the meat as previously mentioned andwhich is sufficient to separate the muscle tissue from the sinew andforce the tissue away from the restrained sinew, while a somewhat lesserforce continues to be independently exerted on the pins 66 by thecylinder 76, but which lesser force is sufficient to restrain the sinewin the meat from sidewise movement and against movement relative to theconveyor 118, the surface 50 of the base plate 48 and the compressionsurface 61. The muscle tissue in the meat M which is separated from thesinew will exude outwardly toward the sides of the pin plate 66 throughthe spaces between the pins 66, as shown by the solid arrows in FIG. 6A,and transversely from beneath the compression assembly 56 and itscompression plate 60 as best seen in FIG. 5.

Once the muscle tissue, which is suitable for the dark colored phase, MThas been separated from the sinew which has been stationarily restrainedby the pins 66, and has been exuded from beneath the compression plate60, the assembly is indexed to its next cycle. As shown in FIGS. 5 and10, when this indexing is initiated, cylinders 140 and 76 are reversed.Reversal of cylinder 140 will result in the raising of the lift assembly32 as shown in FIG. 10, and the piston rod 142, frame 138, lift posts136 and plate 52. Because the cylinder 76, head posts 54 and pressassembly 56 are also mounted to the plate 52, they will also rise awayfrom the conveyor belt 118 together with pin plate 64 and pins 66. Asthe compression surface 61 rises, the web of sinew S which waspreviously restrained and which has now been separated from the meatwill firmly adhere to the surface 61 and will rise with that surface asshown in FIG. 10. The movement of the pin plate 64 relative to thecompression assembly 56 and away from the conveyor belt 118 ispreferably somewhat delayed while the compression assembly is beingraised to cause the ends of the pins 61 to at least initially projectsomewhat beneath the surface 61 during this rising withdrawal. This willsufficiently reduce any tenacious adhesion of the web of sinew S to therising surface 61 so that it may later be more easily removed as will bedescribed to follow.

Once the desinewing unit 130 has been fully raised and withdrawn to theposition shown in FIG. 11, the pin plate 64 will also be fully raised sothat the blunt ends of the pins 66 will have moved into the compressionplate 60 at least to the extent that they are flush with the surface 61.This will permit the web of sinew S to be easily scraped from thesurface 61 as will be further described below.

Either while the desinewing unit 130 is in the process of retraction andraising as viewed in FIG. 10 or once it has become fully raised andretracted as viewed in FIG. 11, the conveyor belt 118 is indexed to movethe just separated whole muscle tissue MT forward and toward the rightend of the conveyor as viewed in FIGS. 5, 10 and 11, and to initiatemovement of a new batch of meat M to be desinewed to a position beneaththe press assembly 56, as progressively shown in FIGS. 10 and 11.

One embodiment of subassembly is shown for the removal of the sinew Swhich has been removed from the muscle tissue, and which has adhered tothe surface 61 after that surface has been raised and withdrawn to theposition shown in FIG. 11. In this sinew web removal subassemblyembodiment, a pair of rodless cylinders 82 are mounted to extendhorizontally and longitudinally of the conveyor belt 118 and within thelift posts 136, but straddling the press assembly 56. Each of therodless cylinders 82 includes a movable carriage 84 which is movableaxially along the length of the cylinder. The carriage 84 of eachcylinder is magnetically coupled to the piston (not shown) within eachof the rodless cylinders 82. A scraper 86 extends between and slightlybeyond the carriages 84 and transversely across the conveyor belt. Thescraper 86 is mounted to the respective carriages 84 by a spring loadedrod 88 which normally urges the scraper 86 upwardly as viewed in thedrawings.

A pair of elongate, spaced parallel camming plates 90, each having adownwardly facing cam surface 92, also extend in a direction generallyparallel to the rodless cylinders 82 and the direction of movement ofthe conveyor belt 118. These camming plates 90 also straddle the pressassembly 56 and pin plate 64, as best seen in FIG. 5, but are positionedjust outside of the rodless cylinders 82 and the cylinders 82 aremounted to them. During each cycle of operation of the desinewing unit130, the scraper 86 is positioned out of action in a retracted positionat one of the elevated ends of the cam surface 92, for example as shownin FIG. 9, until desinewing has been completed. When desinewing has beencompleted and the compression assembly 56, pin plate 64 and pins 66 havebeen raised and withdrawn and the blunt ends of the pins have beenwithdrawn to at least be flush with the surface 61 of the compressionplate 60, all as shown in FIG. 11, the scraper 86 will be movedlongitudinally from one end of the desinewing unit 130 to the other end,as shown by the arrow, along the cam surfaces 92 and beneath the surface61 to scrape the web of sinew S which is stuck to the surface 61 fromthe surface and carry it to the other end of the cam surfaces 92 to bediscarded.

The sinew web removal subassembly embodiment as shown also includes asmall, preferably pneumatically operated cylinder 94 adjacent each endof the rodless cylinder 82. Cylinder 94 operates a pivotally mountedsinew web removal scraping finger 96 for scraping and discharging asinew web S from the scraper 86 which had been removed from the surface61 of the press plate 60 in the last preceding processing cycle. Thesinew web S which is removed from the scraper 86 is deposited by thefingers 96, as shown in FIG. 11, on web removal conveyors 98 whichextend laterally above the conveyor belt for removal of the sinew webs Sfrom the assembly.

The sinew web removal and assembly, as thus far described, operatesessentially as follows. As previously described, substantial compressionforces were applied to the meat M from which the sinew is to be removedbetween the top surface of the conveyor belt as supported by the plate48, and the compression surface 61 of the compression plate 60 while thesinew was restrained with the pins 66 in order to separate the muscletissue from the restrained sinew. Once the muscle tissue MT has beenseparated, the lift assembly 132 will retract the press assembly 56, thepin plate 64 and the pins 66 by moving them upwardly as viewed in FIG.10. During this retraction and upward movement, the blunt ends of thepins 66 are preferably permitted to continue to project somewhat beyondthe compression surface 61 as shown in FIG. 10. As previously mentioned,this assists in the loosening of the web of sinew S which otherwisefirmly and tenaciously adheres to the surface 61 of compression plate60.

Once the compression assembly 56, pin plate 64 and pins 66 have beenfully retracted, they will assume the position as viewed in FIG. 11. Inthis position the pins 66 will now at least be withdrawn to the pointthat their blunt ends are flush with the surface 61. This will permitthe scraper 86 to travel the length of the surface 61 to scrape andremove the web of sinew S which is adhering to it.

Referring to FIGS. 10 and 11, in order to commence the removal of thesinew web S, the rodless cylinders 82 are actuated to move the carriages84 from their left at rest position as viewed in FIG. 6 to the right.This will cause the scraper 86, which is upwardly spring loaded by thepin 88, to move downwardly from the position shown in FIG. 10 as thescraper moves to the right along the cam surface 92. The scraper 86therefore will pass beneath the surface 61 of the press plate 60 toscrape and remove the web of sinew S as shown in FIG. 11. At the sametime that the scraper 86 commences movement from its position as shownin FIG. 10, the cylinder 94 at that position will also be activated.When the cylinder 94 is actuated, it will rotate the scraping finger 96,as shown in FIG. 11, to scrape the web of sinew S which was on thescraper 86 from its previous scraping run, and flip it onto the conveyor98 for removal laterally of the assembly as viewed in FIG. 5.

As the scraper 86 traverses the length of the surface 61, it will scrapeand remove the web of sinew S from that surface and carry it to theright in the direction of the arrow as shown in FIG. 11 until thescraper 86 reaches the other end of its run. At that point, thecarriages 84 and scraper 86 will stop with the just removed web of sinewhanging from the scraper. Thus, the scraper 86 with the just removed webof sinew is now positioned on the right in readiness for the web ofsinew to be removed by the right hand scraping finger 96 during the nextsubsequent indexed processing step.

Although the sinew web removal subassembly has been depicted as beingrelatively stationarily mounted relative to the up and down movement ofthe components of the desinewing unit, it will be appreciated that someor all of the components of the sinew web removal subassembly may bemounted for movement in conjunction with parts of the head assembly 134.For example, the rodless cylinders 82, scraper 86 and camming plates 90may be mounted to and move up and down with either the press assembly 56or the pin plate 64.

Referring to FIG. 12 a typical web of sinew S is depicted as justremoved from the whole muscle tissue by the present invention. The sinewweb S which adheres to the surface 61 as it is raised and scraped, asshown in FIGS. 10 and 11, is a wet and sticky stringy sheet whichresembles to some extent a laced or crocheted appearance of interwovenor interlaced connective tissue T with holes H interspersed in the lacedsheet. It will typically have a rather mottled white to pink to redcoloration depending upon the amount of muscle tissue which has beenseparated from the sinew and the amount which remains with the sinew.The sinew web S will also typically contain a considerable number of fatcells which continue to adhere to the sinew upon separation of themuscle tissue from the sinew. The muscle tissue MT for use in the baconproduct of the invention is still whole muscle tissue which has not beenground or comminuted.

As shown in FIG. 6A, the pins 66 preferably are arranged in a staggeredrelationship to each other to not only form rows and/or columns of pinsat right angles to each other, but also form diagonal rows of pins R andR' with diagonally extending aisles A between the rows R and R'. Thediagonal aisles A are defined by the spaces between respective pins inadjacent rows R and R', and because the aisles A are straight anduninterrupted, they will conduct the muscle tissue MT from the meat Mtoward the sides as shown by the solid arrows in FIG. 6A. From there thedesirable muscle tissue MT can be conveyed away as previously describedfor use in making the bacon product(s). With the diagonal arrangement asseen in FIG. 6A, the amount of desirable muscle tissue being dischargedfrom the ends in the direction of the dotted arrows (and the hollowarrow in which the assembly is indexed) is minimized due to theobstructed tortuous path that the separated muscle tissue must take ifit is to move in that direction. Although a staggered, generallydiagonal pattern is shown and preferred for the reasons stated, otherpin arrangements, such as rectangular or curvilinear positioningrelative to each other, or in which areas are present in which pins havebeen omitted, e.g. cleared areas, are possible and might be preferred incertain circumstances.

In the preferred embodiment illustrated in FIG. 1, the sinew web S is abyproduct which is not used in preparing the bacon product(s). This webmaterial can be discarded or used in other products. The separated wholemuscle tissue MT is the "Lean" of the dark-colored phase. Preferably,this lean dark-colored phase is mixed with water and brine component asgenerally discussed herein in connection with the light-colored phase.When the heme is extracted from the lean component of the light-coloredphase, the water and heme therefrom is added to this dark-colored phase.Thereafter, the dark-colored phase is combined with the light-coloredphase to prepare the desired meat product or meat block.

The combined bacon product is a very low-fat bacon product having eithera homogeneous appearance or an appearance of light and dark streaks.Typically, the bacon product is extruded. For example, the dark-coloredphase and the light-colored phase can be co-extruded into alternatinglayers of light and dark layers in accordance with meat co-extrudingprocedures and equipment as practiced and used heretofore in makingbacon products made of light and dark turkey components which arecurrently sold commercially. Alternatively, a homogeneous product of thetwo lean material phases could be mixed together, and the resultingbatter extruded as a loaf. In either event, the combined product(s) canbe heat processed and/or subjected to smoking conditions, combined withflavoring agents, chilled and then sliced into strips.

In preparing the light-colored phase, a low-fat source is generated byutilizing fatty loin trimmings having between about 20 weight percentand about 70 weight percent fat, based upon the weight of the trimmings.These pork trimmings are processed through equipment as illustrated inFIGS. 2, 3 and 4. The result is a lean meat supply of loin materialwhich has a fat content of less than 1.5 weight percent fat present inthe lean loin material. The dark-colored phase is low-fat lean materialhaving some intact muscle integrity. Muscles are selected from the loin,such as Longissimus dorsi, Gluteus medius and Psoas major. Preferablyportions with obvious marbling are excluded. These muscle pieces aremembrane-skinned and are subjected through processing in desinewingequipment such as that illustrated in FIG. 5 through FIG. 11. The amountof fat in the desinewed lean muscle tissue is at a level of about 2weight percent or less, preferably at about 1.5 weight percent or less,and most preferably at about 1 weight percent or less.

It will be appreciated that, under current U.S. Department ofAgriculture regulations, only muscles from the belly can be used to makea finished product which can be properly identified as bacon.Accordingly, when pork muscles which do not come from the belly, butcome from the loin, are used as noted above, the finished product ismore properly identified as a so-called Canadian bacon product.

Other meat sources can be utilized, including other pork sources. In ageneral sense, the meat sources can include 72 pork, 42 pork, 50 beef,mechanically deboned turkey or other fowl, and other sources of redmeat, white meat, fowl or the like. Particularly suitable for desinewingare meat cuts of good quality before processing and meat cuts which areof only marginal quality before processing. The former are furtherimproved by the processing, while the latter are substantially upgradedin quality and value. Examples of meat cuts which are of good qualityand in which the quality may be further improved include knuckle musclesuch as the Quadriceps femoris muscle, the Rectus femoris muscle and theVastus lateralis muscle; leg muscles such as Semimembranosus and bicepsfemoris muscles; and butt muscle such as the Gluteus medius. Examples ofother meat cuts which may be of only marginal quality but which may besubstantially upgraded include but are not limited to knuckle cap(Tensor fasciae latae); lower and upper shank (Flexur digatorumsuperficialis/profundus and gastrocnemius); tenderloin (Psoas major,Iliacus and Sartorius); portions of the outside muscle (Semitendinosus,Gluteus superficialis, biceps femoris and Gluteobiceps), and top butt(Gluteus accessorius and Gluteus profundus).

The following examples are presented in order to illustrate the presentinvention.

EXAMPLE 1

A Canadian bacon product utilizing pork loin raw materials is prepared.A homogeneous product is prepared from two lean materials. One of thelean materials is made utilizing fatty loin trimmings processed throughthe equipment of FIGS. 2, 3 and 4 in order to separate out the fat andprovide loin material having a fat content of less than 1.5%. The otherlean material is a low-fat lean material with some intact muscleintegrity. This is generated by first selecting muscles from the loin,including Longissimus dorsi, Gluteus medius and Psoas major, excludingportions with obvious marbling. These muscle pieces are membrane-skinnedand desinewed on equipment as illustrated in FIGS. 5 through 11.

These two lean muscle materials are added to a mixer. Brine componentsincluding water, salt, sodium nitrite, sodium phosphate, sugar, sodiumascorbate and other flavorings are mixed for a time sufficient toachieve a desired protein extraction. Water level is then controlled toUSDA regulations. The resulting batter is then extruded as a loaf, heatprocessed, chilled and then sliced into strips of Canadian baconproduct.

EXAMPLE 2

A two-phase bacon product having light and dark streaks is made toprovide a product having the appearance of pork belly bacon. Aco-extrusion procedure is followed as illustrated in FIG. 1.

Fatty loin trimmings are ground, heated and centrifuged in the presenceof a phosphate source as illustrated in FIGS. 2-4. The lean product ismixed with water to extract heme pigments from the lean centrifugate.Same is emulsified with brine components, with reduction to very smallparticle sizes occurring during emulsification so as to result in alighter color. Enhanced light color is achieved by higher temperatureemulsification, such as above 15° C., but not so high as to denature themeat protein. This results in a significantly lighter color.

The dark-colored phase begins with loin muscles which aremembrane-skinned, followed by the desinewing operation as discussedherein. The resulting web material is discarded, while the desinewedlean meat is then mixed with water and the heme extraction from thelight-colored phase, together with brine components as desired.Temperatures are maintained well below 15° C. so as to result in adarker color.

The resulting light-colored phase and darkcolored phase are thenco-extruded with equipment suitable for forming a bacon belly appearingslab. The resulting slab is processed as is a bacon belly, includingcuring, heating and smoking, followed by chilling, slicing into stripsand packaging within a protective environment.

EXAMPLE 3

Batches of 72 pork are processed through the apparatus as generallyillustrated in FIG. 2 through FIG. 4. Sodium tripolyphosphate is addedat an upstream location, being added to the pork trimmings prior toentry into the comminution unit. With the sodium tripolyphosphate addedat a level of 0.5%, based upon the total weight of the meat, theresulting lean component exiting the centrifuge has an average fatcontent of about 0.84 weight percent. This is used as the light-coloredphase in the FIG. 1 process.

This is combined with a dark-colored phase. Trimmed pork cuts aresubjected to connective membrane skinning and processed throughdesinewing equipment as illustrated herein. The force on the pins isabout 3500 pounds, and the force on the compression assembly is about8000 pounds. The pins are cylindrical and 6.4 mm in diameter, are spacedapart 7.6 mm on centers, and are 650 in number. The compression surfaceof the compression plate is 25.4 cm by 38 cm. As processed, the productis 70 weight percent lean muscle tissue and 30 weight percent sinew web.Analysis indicates that the processed lean muscle desinewed tissue has1.9 weight percent fat when the initial meat is pork lower shank, 1.5weight percent fat when the initial meat product is pork front shank,1.07 and 0.7 weight percent fat when the initial product is pork uppershank, and 2.5 weight percent fat when the initial meat product is wholeturkey thighs.

The resulting co-extruded product, when an all-pork product, aftersmoking, chilling and slicing has a taste and texture approximating thatof natural pork belly bacon when an all-pork product is prepared.

It will be understood that the embodiments of the present inventionwhich have been described are illustrative of the principles of thepresent invention. Numerous modifications may be made by those skilledin the art without departing from the true spirit and scope of theinvention.

We claim:
 1. A process for preparing a bacon product, comprising thesteps of:preparing a first low-fat meat phase from a supply ofcomminuted meat having a fat content of between about 5% and about 60%by weight, based upon the total weight of the meat, said preparingincluding:heating said supply of meat to a temperature adequate togenerally melt fat within the supply of meat without significantlydenaturing the meat, passing the flow of heated comminuted meat into acentrifuge to subject said flow to a gravitational force sufficient toseparate said flow into a lean meat phase and a high fat phase, andcollecting the lean meat phase, said lean meat phase being said firstlow-fat meat phase from the centrifuge, said first low-fat meat phasehaving a fat content of not greater than about 5 percent by weight offat, based upon the total weight of the first low-fat meat phase;forming a second low-fat meat phase from a supply of meat having muscletissue and sinew, said forming including:restraining the sinew againstmovement relative to a surface, imparting a compressive force to themuscle tissue in a direction toward said surface while restraining thesinew, said force being sufficient to separate the muscle tissue fromthe sinew and cause the muscle tissue to move away from the restrainedsinew in a direction at a substantial angle to the direction at whichthe compressive force is imparted to the muscle tissue, and collectingthe muscle tissue thus separated, said muscle tissue being said secondlow-fat meat phase, said second low-fat meat phase having a fat contentof not greater than about 5 percent by weight of fat, based upon thetotal weight of the second low-fat meat phase; and combining said firstlow-fat meat phase and said second low-fat meat phase into a baconproduct.
 2. The process in accordance with claim 1, wherein saidcombining step mixes said first low-fat meat phase together with saidsecond low-fat meat phase.
 3. The process in accordance with claim 2,wherein said bacon product is a Canadian bacon, both of said preparingand forming steps including providing pork meat.
 4. The process inaccordance with claim 1, wherein said combining step includesco-extruding said first low-fat meat phase with said second low-fat meatphase to provide said bacon product with different phases which arevisibly distinct from each other.
 5. The process in accordance withclaim 4, wherein said co-extruding step forms a block of meat having anappearance which generally approximates that of a bacon belly, saidfirst low-fat meat phase being a light-colored phase, and said secondlow-fat meat phase being a dark-colored phase.
 6. The process inaccordance with claim 5, wherein both of said preparing and formingsteps include providing pork meat.
 7. The process in accordance withclaim 1, further including extracting heme pigments from said firstlow-fat meat phase to provide a heme extract, and mixing said hemeextract with said second low-fat meat phase, said mixing being prior tosaid combining step.
 8. The process in accordance with claim 1, furtherincluding emulsifying said first low-fat meat phase, said emulsifyingbeing carried out at a temperature not lower than 15° C.
 9. The processin accordance with claim 1, further including adding a phosphate sourceto said supply of meat for said first low-fat meat phase, said phosphatesource being added at a quantity of about 0.5 percent by weight or lessof phosphate, based upon the total weight of the meat supply.
 10. Theprocess in accordance with claim 9, further including a flowing stepbetween said heating step and said passing step, said flowing stepproviding a flow of heated comminuted meat having dispersed therewithinphosphate from said phosphate source, and said passing step includingpassing a flow of the heated meat and phosphate from said flowing stepinto said centrifuge.
 11. The process in accordance with claim 1,wherein each of said steps maintains functionality in the meat such thateach of said first low-fat meat phase and said second low-fat meat phasehas a functionality of at least about 4, functionality being the ratioof water-holding capacity to protein percentage of the respective meat.12. The process in accordance with claim 1, wherein the temperature ofsaid heating step is not greater than about 46° C.
 13. The process inaccordance with claim 1, wherein each of said first and second low-fatmeat phases has a fat content of approximately 3.5 weight percent orless, based upon the total weight of the respective low-fat meat phase.14. The process in accordance with claim 1, wherein each of said firstand second low-fat meat phases has a fat content of approximately 2weight percent or less, based upon the total weight of the respectivelow-fat meat phase.
 15. The process in accordance with claim 1, whereineach of said first and second low-fat meat phases has a fat content ofapproximately 1 weight percent or less, based upon the total weight ofthe respective low-fat meat phase.
 16. The process in accordance withclaim 1, wherein said first low-fat meat phase has a fat content ofapproximately 1 weight percent or less.
 17. The process in accordancewith claim 1, wherein said restraining step includes piercing the meatfrom which the sinew is to be separated.
 18. The process in accordancewith claim 1, wherein said restraining step includes restraining thesinew by a plurality of elongated pins which are spaced from each otherin a direction substantially perpendicular to the longitudinal axes ofthe pins.
 19. The process in accordance with claim 18, wherein duringthe imparting step the muscle tissue moves through the spaces betweenthe pins and away from the restrained sinew.
 20. The process inaccordance with claim 1, wherein the meat from which the sinew is to beseparated is positioned between a pair of surfaces, and the surfaces arebrought together with the meat therebetween to impart the compressiveforce thereto to separate the muscle tissue from the sinew and cause themuscle tissue to move in a direction substantially parallel to at leastone of said surfaces.
 21. The process in accordance with claim 20,wherein said sinew is restrained against movement relative to at leastone of said surfaces.
 22. The process in accordance with claim 1,wherein said imparting step also includes the removal of substantialamounts of fat associated with the sinew that is removed from the meat,said fat being restrained with the sinew with which it is associatedwhile said compressive force is imparted to the muscle tissue toseparate the muscle tissue from both the sinew and the fat associatedwith the sinew.